That's how long the whole process took, operating table to opening pitch.

That's just short of 500 days. It felt like an eternity.

On Oct. 22, 2013, Dr. James Andrews replaced the torn ulnar collateral ligament inside Matt Harvey's precious right elbow with a tendon he farmed from the pitcher's left wrist.

On March 6, Harvey walked to the mound at Tradition Field, in front of a standing-room-only crowd, and fired a 96-mph fastball to the Tigers' leadoff hitter, Anthony Gose.

Said Mets pitching coach Dan Warthen, "It looked like he never missed a beat.''

From that day forward, when surgeons talk about best-case scenarios involving Tommy John surgery, they will invoke Matt Harvey's name.

Aside from the occasional headache Harvey gave the Mets when they argued over minor points during his rehab -- such as staying in New York City vs. Port St. Lucie -- the entire process was relatively seamless.

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What Harvey went through, as did the hundreds of Tommy John patients who preceded him, is not as uncomplicated as he made it appear. Outside of the pitcher himself, the doctors, the rehab staff and maybe the team's front office, few people actually understand what coming back from ligament-replacement surgery truly involves.

To the uninitiated, it's the equivalent of a 14-to-16-month sabbatical, an extended period of rest and recovery and then, inevitably, the return date.

What people often fail to realize is that Tommy John surgery -- even with success stories such as Harvey's -- remains a very serious operation with a great deal of uncertainty still attached for years afterward.

Same pitcher? No guarantees

"A normal person has surgery, and you build yourself up, you rehab yourself to the point of functioning on a daily basis,'' said Jon Debus, now in his fifth year as the Mets' rehabilitation pitching coordinator. "We're asking a guy to function on a daily basis and also compete at the major-league level. That's a pretty tough task.''

With no guarantees. The American Journal of Sports Medicine recently published three different studies that examined the post-op situations of Tommy John patients, with varying results.

One of those studies, authored in part by Yankees orthopedist Christopher Ahmad, reviewed the cases of 147 pitchers, from 1999 to 2011, and found that 80 percent returned to pitch in at least one major-league game. That dropped to 67 percent when the criteria changed to "returned to the same level of competition,'' and 57 percent eventually went back on the disabled list with some sort of arm injury.

Perhaps most alarming? This same study concluded that "performance declines across several major metrics after surgery'' and that Tommy John surgery patients "should be counseled appropriately'' regarding the long-term prognosis.

In other words, the study seems to reinforce that nonsurgical options are best explored first, when applicable.

For such an example, look no further than Yankees Opening Day starter Masahiro Tanaka, who was diagnosed with a very small UCL tear last July. At that point, it was assumed that Tanaka would need Tommy John surgery. The Yankees sought numerous opinions, and every doctor recommended trying a more conservative approach -- eight weeks off and a regimen of platelet-rich plasma injections to promote healing in the elbow.

So far, that plan has worked. Tanaka is not reporting any pain and remains an effective pitcher, replacing CC Sabathia as the Yankees' No. 1. Had he suffered a bigger tear and required Tommy John surgery, he'd be in his eighth month of rehab right now and looking at a possible September return. Only time will tell if he was fortunate to avoid surgery -- or unlucky that he turned out to be just delaying the inevitable.

"I feel it's healed,'' Tanaka said. "I'm confident I can get through the season.''

Argument for delaying surgery

There are precedents for what Tanaka is trying to do, successfully managing a minor tear over a period of time. The Cardinals' Adam Wainwright was diagnosed with a partial UCL tear in high school, and again when he was in Triple-A, but put off surgery and pitched 182 games in the majors -- 99 starts -- before ultimately needing Tommy John surgery after the 2010 season, when he finished second in the Cy Young voting (20-11, 2.42 ERA, 230 innings).

Wainwright missed the entire 2011 season but is a combined 53-31 (.631) with a 3.05 ERA in three years since the surgery. He's also averaged more than 222 innings a season during that span.

Even with his post-op success, Wainwright advocates delaying Tommy John surgery for as long as possible, if the tear is an acceptable size.

"It gets kind of cloudy in the middle ranges,'' Wainwright said. "Where I was, you've got a chance. And it's worth the rehab process because I've been through it and I've proved that you can come back. I pitched six years, very well, at a high level in the big leagues. I closed out a World Series, pitched 200-plus innings a few times. And I never thought of my elbow.''

Of course, that strategy doesn't always work, as the Mets' Jacob deGrom learned at the start of his career. A ninth-round draft pick out of Stetson University in 2010, deGrom struggled through six starts at rookie-level Kingsport that year before the discomfort in his right elbow got him shipped to New York for an MRI.

"I didn't want to say anything,'' deGrom said. "I was kind of scared to say something, but I was like, 'Seriously, what's going on here?' It was like that for four or five starts, then I figured I'd better say something because it's not getting any better. It was miserable pain. Mine was pretty sharp.''

The first MRI found a small tear, but the initial recommendation was rehab, and deGrom spent 2 1/2 months hoping the pain would go away. Although he didn't throw a baseball again, it never did. Finally, in October, deGrom flew to New York again for another MRI. That same morning, he saw Mets orthopedist David Altchek, who told him he needed Tommy John surgery.

He didn't have much chance to think it over. DeGrom asked when, and Altcheck's answer was 3:30 that afternoon.

Fortunately, the process went smoothly for deGrom. Looking back, he believes it might have been the best thing that could have happened to him. The lengthy rehab process taught him the importance of routine and focusing on his mechanics.

When deGrom did return to the mound, after nearly 17 months, the results surprised him. His velocity had increased dramatically.

"Someone came up to me and said I was at 96 and hit 98,'' deGrom recalled. "That was the funny thing. I had never thrown that hard before. But it was all starting to feel really good. The ball was coming out really good.''

Two years later, deGrom was a surprise call-up by the Mets last season -- and went 9-6 with a 2.69 ERA in 22 starts to earn Rookie of the Year honors at age 26.

It was a skyrocket rise for the unheralded deGrom, and the launching pad was tucked away behind Tradition Field, where the Mets have their rehab facility and the recovering pitchers have nothing but time on their hands.

"It's four months of being scared,'' Debus said. "The stress of the surgery and wondering if you're ever going to throw again, because there's always that chance that it doesn't work. It's not an exact science. And it's a grind.''

Nowhere close to prevention

The Mets are sort of the home office for Tommy John surgery. They have four functioning post-op pitchers on their major-league roster, and another, former Ward Melville star Steven Matz, down at Triple-A Las Vegas. In addition, the Mets lost two more -- Zack Wheeler and Josh Edgin -- in a span of two weeks during spring training.

At one point in late March, Edgin had just returned to the Tradition Field clubhouse, his left arm heavily bandaged, as Wheeler was preparing to fly to New York to have the surgery performed by Altchek.

Traumatic for the pitchers, certainly. But it's also chaotic for a team as it tries to put a staff together for the regular season. From the start of spring training to the end of October, the specter of Tommy John surgery haunts every club. It's always in the back of a general manager's mind.

"It has to be,'' Mets general manager Sandy Alderson said. "I can't say that it was two or three years ago. But it has to be now. It's like a daily proposition. You start looking at the percentages. You're thinking, well, I got 30 pitchers in camp, and what percentage of major league pitchers have had that surgery. The statistical probability is that somebody's going to have an issue.''

Matz is on track for a call-up at some point this season, but his experience with Tommy John surgery to repair an 80 percent tear is a cautionary tale. Rather than the anticipated rehab of 14 to 16 months, Matz endured a pain-filled, stop-and-start nightmare that delayed his return for two years. After countless MRIs and worry about a potential new tear, Andrews, who believed it was not a structural issue, finally told Matz to pitch through the discomfort.

"It was scar tissue, or the new ligament wasn't fully matured yet,'' Matz said. "So it just kind of took longer for me.''

All eyes will be on Harvey this season because he is coming back from Tommy John surgery. Tanaka will be under the same intense scrutiny for holding off on the procedure. Two aces connected by the same ulnar collateral ligament, both of them members of an ever-growing baseball fraternity that no pitcher wants to be a part of.

"It's an issue we've spent a lot of time on,'' said new commissioner Rob Manfred, who took over for Bud Selig in January. "We're looking at health history, the physiology of the pitchers, the biomechanics of the delivery, trying to figure out if there are particular tendencies or characteristics that make people more prone to have this type of injury.''

Someday a reliable course of prevention may be able to curb the staggering number of Tommy John surgeries, but baseball is nowhere close to that yet. Pitchers these days seem to face the same physical risks as lumberjacks or bike messengers. When elbows are involved, there just isn't an explanation why some require surgery and others don't.

"You see big guys, you see small guys, you see all kinds of guys getting Tommy John,'' said Sabathia, who has never needed it despite throwing 2,821 innings in 14 seasons. "I just think it's luck of the draw.''